Design of ZnFeAlO4/Zn-SAPO-34 composite catalyst for selective hydrogenation of CO2 to propane

Abstract

Catalytic hydrogenation of CO2 into a single product provides a promising strategy for recycling and utilizing this greenhouse gas, but it remains challenge. Herein, a ZnFeAlO4/Zn-SAPO-34 composite catalyst has been designed, which exhibits a space-time yield of propane of 4.21 mmol g−1 h−1, along with a long-term stability of over 180 h. It was found that the Fe sites in ZnFeAlO4 spinel are conductive to accelerate CO2 hydrogenation into CH3OH, which are stable enough to prevent reduction and carbonization. Characterization results proved that more Brønsted acid sites of SAPO-34 and the addition of Zn species into SAPO-34 zeolite are favorable to form active methylbenzenes with four or five methyl groups, preferentially leading to the formation of propylene via the aromatics-based cycle, which could be hydrogenated to propane. This work presents a feasible strategy in designing an efficient composite catalyst for the synthesis of specific single products from CO2 hydrogenation.